Microelectromechanical systems (MEMS) have recently been developed as alternatives for conventional electromechanical devices such as relays, actuators, valves and sensors. MEMS devices are potentially low cost devices, due to the use of microelectronic fabrication techniques. New functionality may also be provided because MEMS devices can be much smaller than conventional electromechanical devices.
Many potential applications of MEMS technology utilize MEMS actuators. For example, many sensors, valves and positioners use actuators for movement. If properly designed, MEMS actuators can produce useful forces and displacement, while consuming reasonable amounts of power. Many configurations of MEMS actuators have been proposed. For example, U.S. Pat. No. 5,475,318 to Marcus et al. entitled "Microprobe", discloses cantilever bimorph microprobes and doubly supported beam bimorph microprobes. In addition, an article entitled "Silicon Fusion Bonding and Deep Reactive Ion Etching; A New Technology For Microstructures", by Erno H. Klaassen, et al. presented at the International Conference on Solid-Date Sensors and Actuators, Transducers '95 held in Stockholm, Sweden in June 1995 describes a thermal actuator having a pair of arched beams extending between a pair of supports. By current through the arched beams, the arched beams will expand so as to further arched. The thermal actuator of the Klaassen article can also a include a center post that connects the plurality of arched beams and serves to push against the workpiece. The Klaassen article also describes a capacitive accelerometer structure that utilizes the thermal actuators to vary the spacing between a number of interdigitated fingers.
Notwithstanding the MEMS actuators that have previously been proposed, a number of existing and contemplated MEMS systems, such as relays, actuators, valves and sensors, require more sophisticated actuators that provide useful forces and displacements while consuming reasonable amounts of power in an efficient manner. Since it is desirable that the resulting MEMS systems be fabricated with batch processing, it is also preferred that the microelectronic fabrication techniques for manufacturing the resulting MEMS systems be affordable, repeatable and reliable.